Default address (cPanel)
The default address (also known as catch-all) determines what happens to email sent to an email address that doesn't have an email account, forwarder or auto-responder set up for it. In other words, it "catches" emails going to a non-existent address.
Options for default address
This image shows the various options for the default address in cPanel. Each option is explained below.
Forward to email address
Use this option to forward incorrectly addressed email to another email address. This could represent an actual mailbox or a forwarder, either on your own domain or anywhere else.
Discard with error to sender
Due to the amount of spam being sent to random email addresses, this is usually the recommended option. Any incorrectly addressed email is returned to the sender with a message of your choice, eg "No such address". This email "bounce" happens at the SMTP stage, which means the email never actually enters the email queue, and therefore uses very few system resources. This option is equivalent to sending the email to :fail: in earlier cPanel versions.
Discard (not recommended)
If you select this option, any incorrectly addressed email just disappears without trace, and no notification is sent to the sender. This option is not recommended because each email will go through the mail queue, and be processed by email filters and spam or virus software, so tends to consume greater server resources. This option is equivalent to sending the email to :blackhole: in earlier cPanel versions.